Interchangeable camera lenses with click-stop devices for the diaphragm rotating rings thereof are known.
The object of these click-stop devices is to provide the user with haptic and/or acoustic feedback relating to the adjustment of the diaphragm rotating rings. By way of example, click-stop grooves may be provided at the typical f-number settings 22-11-8-5.6-4-2.8-2. Then, the user can quickly find the correct f-number setting for his photographs.
However, such click-stop devices are disadvantageous for those users who wish to use interchangeable camera lenses for producing a film. These days, most digital system cameras, for example digital single-lens reflex cameras and mirrorless system cameras, provide the option of making photographs and producing videos.
Here, a system camera is understood to mean a camera which includes interchangeable components within a fully compatible camera system. In general, a system camera includes a camera and interchangeable lens.
While amateurs often work using standard autofocus lenses, more ambitious amateurs and professional cameramen often use manual lenses in order to shoot relatively high-quality films using this alternative which, compared to professional camera equipment, is compact and cost effective. Here, direct control over focus and diaphragm should be enabled.
Commercially available manual lenses are designed for photographic applications and therefore have the aforementioned click-stop mechanism on the diaphragm rotating ring, the click-stop mechanism enabling an adjustment in steps, usually in half f-number steps. The spacing of the steps in this case usually corresponds to what the camera can usefully process for forming exposure time/diaphragm combinations.
This click-stop mechanism is bothersome when recording moving images since a continuous, that is, step-less, diaphragm adjustment, which avoids brightness jumps in the image, is advantageous during filming.
Users who nevertheless want a continuous adjustment therefore often convert the lenses by virtue of removing the click-stop sphere and spring. To this end, several parts on the lens have to be disassembled, which may lead to misalignment or damage in the case of an unskilled execution. Ultimately, the user also invalidates the warranty by these interventions.
The prior art has disclosed lenses with click-stop devices in which the click-stop device continues to be effective in an active work position. In a passive work position, the click-stop device is then ineffective, that is, the diaphragm rotating ring can then be set continuously.
Lenses with such click-stop devices are known from, for example, DE2725404A1, CH350541 and United States patent application publication 2013/0163979A1.
In the case of known click-stop devices, a click-stop sphere sits on a click-stop spring in a bore in the main barrel. A disadvantage of the known click-stop devices is that a component is pushed between the click-stop sphere and the click-stop groove there in order to remove the click-stop effect. However, the pressure on the click-stop sphere by the compression spring remains such that the click-stop sphere now in turn tries to press the component into the click-stop groove. Therefore, a certain amount of pressure is maintained, even in the deactivated state, and the diaphragm rotating ring only moves on the main barrel with increased friction. A further disadvantage lies in the fact that external switching levers are provided in the known prior art, and these could be actuated inadvertently while recording the film.